Huang Lei, Geng Fang-Dong, Fan Jing-Jing, Zhai Wei, Xue Cheng, Zhang Xiao-Hui, Ren Yi, Kang Ju-Qing
National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi 710119, China.
Plant Divers. 2021 Jun 29;44(2):153-162. doi: 10.1016/j.pld.2021.06.006. eCollection 2022 Mar.
Spurs have played an important role in the radiation of the genus , but little is known about how the spurless state arose in . Here we aim to characterize the genetic divergence within and gain insights into the origin of this species. A total of 19 populations from and 23 populations from three of its closest relatives (, and ) were sampled in this study. We sequenced fifteen nuclear gene fragments across the genome and three chloroplast loci to conduct phylogenetic, PCoA and STRUCTURE analyses. Our analyses indicate that may not be monophyletic and can be divided into two distinct lineages ( I and II). I is genetically close to , whereas II is close to . Isolation-with-migration analysis suggested that historical gene flow was low between I and , as well as between II and . The two distinct lineages of show significant divergence in 13 floral traits and also have distinct distributions. In addition, both I and II are adapted to a stony environment that differs from that of their closest relatives, indicating a habitat shift may have driven new adaptations. Our findings enrich the understanding of how floral evolution contributes to species diversification.
距瓣尾囊草属植物的距在该属的辐射演化中发挥了重要作用，但对于无距状态在距瓣尾囊草属中是如何产生的却知之甚少。在此，我们旨在描述距瓣尾囊草属内的遗传分化，并深入了解该物种的起源。本研究共采集了来自距瓣尾囊草的19个居群以及与其关系最近的三个近缘物种（尾囊草、疏花尾囊草和城口尾囊草）的23个居群。我们对全基因组的15个核基因片段和三个叶绿体基因座进行了测序，以开展系统发育分析、主坐标分析（PCoA）和群体结构分析（STRUCTURE）。我们的分析表明，距瓣尾囊草可能不是单系类群，可分为两个不同的谱系（距瓣尾囊草谱系I和距瓣尾囊草谱系II）。距瓣尾囊草谱系I在遗传上与尾囊草接近，而距瓣尾囊草谱系II则与疏花尾囊草接近。隔离-迁移分析表明，距瓣尾囊草谱系I与尾囊草之间以及距瓣尾囊草谱系II与疏花尾囊草之间的历史基因流较低。距瓣尾囊草的这两个不同谱系在13个花部性状上表现出显著差异，且分布也不同。此外，距瓣尾囊草谱系I和谱系II均适应了与其关系最近的近缘物种不同的多石环境，这表明栖息地的转变可能推动了新的适应性进化。我们的研究结果丰富了对花部进化如何促进物种多样化的理解。
